| 1. |
- Andersson, Christian, et al.
(author)
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Improvements in classification of power system security
- 2006
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In: IEEE Power Engineering Society General Meeting, 2006. - 1424404932 ; , s. 6-6
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Conference paper (peer-reviewed)abstract
- In this paper power system security is estimated with a linear support vector machine (SVM). The SVM is used to calculate a hyperplane which separate states of the power system that sustain an (n-1) fault from states that do not. The hyperplane can be used on-line in order to determine if the system is moving into insecure conditions. The proposed method is developed to support operators at control centers and make it easier to make decisions in stressed operating situations. This paper shows that the scaling of variables is important in order to obtain good results. A new method to scale and reduce the number of measured variables is presented. The problem with a data set consisting of both continuous and binary variables is also discussed.
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| 2. |
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| 3. |
- Larsson, Anders, et al.
(author)
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Measurement of current taken by fluorescent lights in the frequency range 2-150 kHz
- 2006
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In: IEEE Power Engineering Society general meeting, 2006. - Piscataway, NJ : IEEE Communications Society. - 1424404932
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Conference paper (peer-reviewed)abstract
- This paper discusses measurements taken on fluorescent lights in the frequency range between 2 and 150 kHz. The presentation of the measurement results form an important part of the paper. The measurement results are presented in time-domain, in the frequency domain and in the time-frequency domain (by means of a "spectrogram"). The latter allows the study of sub-cycle changes in the current spectrum. The current taken by one lamp is compared with the current taken by two, three and four lamps. The relative high-frequency distortion reduced for frequencies above 15 kHz.
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| 4. |
- Lundmark, Martin, et al.
(author)
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Unintended consequences of limiting high-frequency emission by small end-user equipment
- 2006
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In: IEEE Power Engineering Society General Meeting. - Piscataway, NJ : IEEE Communications Society. - 1424404932
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Conference paper (peer-reviewed)abstract
- This paper discusses some consequences of developments in technologies that may impact the risk of electromagnetic interference and equipment damage despite the equipment complying with the tests according to the product standards. Examples of such technologies are: the change from analogue to digital communication, the fast increase in numbers of power converters having smart switching technology and the use of communication via the power system. The paper discusses upcoming sources of emission, uncertainties in emission level, and changing circumstances. It is shown that it is possible for equipment to remain below the emission limits while at the same time the disturbance level increases beyond what was intended by the standard document. The paper also proposes a framework for addressing the problems due to massive penetration of equipment injecting high-frequency harmonics.
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| 5. |
- Nordman, Mikael, et al.
(author)
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Considerations on maintenance strategies for data communication assets in power distribution utilities
- 2006
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In: 2006 POWER ENGINEERING SOCIETY GENERAL MEETING, VOLS 1-9. - Montreal, QC : IEEE. - 1424404932 - 9781424404933 ; , s. 3143-3149
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Conference paper (peer-reviewed)abstract
- The last ten years have seen a steadily growing awareness across industries of the benefits of asset management. In the power industry, asset management has primarily focused on means to extend the lifetime of the transformers, cables, switchgear, and other critical components needed for the secure delivery of energy to the customers. However, with the new distribution automation concepts, with more distributed generation integrated within the power network and with a higher integration between the power system and the services of information systems, the importance of up-to-date and available information and communication services is growing. The maintenance of these service systems have nevertheless up to now not been structurally managed by the utilities. In this paper, the maintenance and management of the data communication systems of power utilities are considered. First, different aspects regarding the organizational issues are discussed. Then some key concepts of telecommunication management and information models for utility data are assessed. Results from case studies on the maintenance of the data communication resources in two power utilities with activities in both urban and rural areas, are presented. According to the findings in the case studies, the applicability of the different maintenance organizations, management support and maintenance methodology is assessed.
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| 6. |
- Xie, Hailian, et al.
(author)
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Novel flux modulated positive and negative sequence deadbeat current control of voltage source converters
- 2006
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In: IEEE POWER ENG SOC GEN MEETIN. - 1424404932 - 9781424404933 ; , s. 533-540
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Conference paper (peer-reviewed)abstract
- Voltage source converters are widely used in the power system to enhance the power system performance. In the conventional converter control, the control system usually takes the voltage measured at the point where the converter is connected and calculates the reference voltage for the converter; with a modulation system the converter then produces the required 'average voltage'. In this paper, a novel flux modulation scheme, combined with the deadbeat current control strategy, is proposed. The current controller is capable of controlling both positive and negative sequence currents. With flux modulation, the control system measures the bus flux and commands the converter to generate the required flux. The simulation and experimental results presented show a good performance of this converter control system.
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